Facing the truth: We trust ourselves

[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/DeBruineMorphs200.JPG” caption=”Morphed faces”]A McMaster researcher used a “face morphing” technique in a new study that shows people find others who look like them more trustworthy.

Studies have shown that animals, such as ground squirrels, favour others that resemble them – something called kin selection.

Evolutionary psychologist Lisa DeBruine devised a game that let players bargain for money to determine if facial resemblance enhances trust in humans.

“The most important aspect of this research is that it establishes a previously unknown phenomenon: facial resemblance can affect social behaviour,” said DeBruine, who recently won the new investigator competition from the Human Behaviour and Evolution Society. “This finding is consistent with an interpretation informed by kin selection theory, but more work will need to be done to support that idea.” Her findings are reported in today's (July 12) edition of the journal Science.

DeBruine, a second-year PhD student, set up a computer game for two people which gave the players the choice of dividing a few dollars equally or trusting the other player to divide a larger amount.

In each case, the participants – 24 McMaster students and 24 control subjects – interacted individually with 16 partners, whose faces were shown on a monitor. All of the faces – pictures from 24 students at the University of Guelph – were altered using the “face morphing” technique. The participant's face was blended with the face of a stranger for half the playing partners and in the other half, two strangers' faces were blended together. Another 24 McMaster students played in a control situation, where they saw the same faces as the other participants, none of which was morphed with their own. (Face morphing examples are available in jpeg format.)

DeBruine's research, reported in the July 7 issue of the Proceedings of the Royal Society of London, found that the participants trusted players with faces resembling their own more than two times out of three. They trusted unfamiliar faces only half of the time. Control participants showed no difference in trust towards faces that had been morphed with the other participants.

DeBruine also ran a study with morphs of celebrity faces such as Ben Affleck and Sarah Michelle Gellar to determine if the players were simply responding to a familiar face and finding it more trustworthy. Her research showed that it was only when there was a facial resemblance that the subjects exhibited confidence in the other player.

Photo caption: Subject's faces (left) were morphed with unfamiliar faces (right) to make the centre faces used in the study. The female morph draws on shape and color information from both faces, whereas the male draws only shape information from the unknown face. Credit: Lisa DeBruine